\newtcbox{\highlight}[1][yellow]{on line,
% sharp corners=south,
arc=0mm,outer arc=0mm,colback=#1!10!white,colframe=#1!50!black,
boxsep=0pt,left=1pt,right=1pt,top=1pt,bottom=1pt,
boxrule=-0.1pt,bottomrule=1pt}

\newtcbox{\highunderline}[1][red]{
    on line,
    % sharp corners=south,
    arc=0mm,outer arc=0mm, colback=white,colframe=#1!50!black,
    boxsep=0pt,left=1pt,right=1pt,top=1pt,bottom=1pt,
    boxrule=-0.1pt,bottomrule=1pt
}

